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Indiana University Studies 



used 3,950 pounds 40 per cent and 2,000 pounds 50 per cent, cost per cubic 

 yard being about .038 cents. 



Sixteen 70-foot holes, face burden of 25 feet, spaced about 15 feet apart; 

 approximately 15,000 cubic yards, for which was used 3,750 pounds 60 per 

 cent, 4,050 pounds 40 per cent making a cost per cubic yard of about .068 

 cents. 



Another nine 50-foot hole blast, spaced 18 feet apart, with 25-foot face 

 burden; approximately 7,500 cubic yards for which there was used 3,250 

 pounds 40 per cent, making cost of .055 cents per cubic yard. 



Seven 60-foot holes spaced 15 feet apart with about 20 feet face burden, 

 approximately 4,600 cubic yards. For this was used 500 pounds 60 per cent, 

 2,900 pounds 40 per cent making cost of .095 cents per cubic yard. 



Eight holes which ran from 80 to 108 feet in depth spaced 27 feet apart, 

 with 30-foot face. There was about 22,000 cubic yards in this shot, for 

 which there was used 2,200 pounds blasting gelatin, 3,350 pounds 60 per cent 

 and 1,200 pounds 40 per cent, making cost of about .055 cents per cubic 

 yard. 



Another eight 48-foot hole blast, spaced 18 feet apart, with 20-foot 

 face burden, approximately 4,500 cubic yards, for which there was 

 used 3,300 pounds of 50 per cent making average cost of about 10 cents per 

 cubic yard. 



A nine 62-foot hole blast, with a 32-foot face burden, spaced about 20 

 feet apart; approximately 13,300 cubic yards. Used 2,500 pounds 60 per 

 cent and 1,800 pounds 40 per cent making average cost of about .045 cents 

 per cubic yard. 



A fourteen 86-foot hole blast, spaced 18 feet apart, with a 30-foot face 

 burden, making approximately 24,000 cubic yards. Used 850 pounds 

 50 per cent, 3,250 pounds 40 per cent, and 4,000 pounds 60 per cent mak- 

 ing cost of about .046 cents per cubic yard. 



Another shot was five 85-foot holes, spaced 18 feet apart, with about 25- 

 foot face burden. About 5,000 cubic yards, for which there was used 1,300 

 pounds 60 per cent and 1,000 pounds 35 per cent. This cost about .06 

 cents per cubic yard. 



These figures are taken from various sections of the country, not being 

 confined to any particular locality, and we have figured the explosives on 

 basis of 123^ cents for the 40 per cent, 13.7 cents for the 50 per cent, and 

 14.9 cents for the 60 per cent, and 25 cents for the blasting gelatin. These 

 are about the average figures, and of course vary according to the location. 



Thinking perhaps you might be interested in the comparative cost between 

 the steam or air di'ill and the well drill system: 



One of our technical men made a close study of this and found that the 

 cost of drilling with an ordinary tripod drill varies from 10 cents to 25 cents 

 per foot, this wide variation depending on the nature of the rock, cost of 

 labor, fuel, oil, the number of drills in operation, and the accessibility to 

 source of power, water, etc. The fewer the drills in operation, if run from a 

 central power plant, the higher the cost per foot. 



In rock of medium hardness, such as limestone, a man working industri- 

 ously should average about 50 or 60 feet of hole per 10-hour day. The cost 

 of drilling such rock seldom falls below 15 cents per foot in a quarry operating 

 several drills. 



